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NASA has a long road ahead in its quest to be able to provide
foods to astronauts with super-long shelf life, a necessity for
missions to Mars and other destinations in the solar system.

Scientists recently tested 13 items that had been stored for
three years, exposed them to temperatures of about 95 degrees
Fahrenheit to simulate another two years of storage and then
extrapolated the results to 65 entrees, based on the ingredients.
Most of the foods are available to astronauts living on the
International Space Station.

"We don't have refrigerators and freezers for food and so all of
our food has to be shelf-stable. We process it so it's either
going to be thermostabilized like a canned product in a pouch, or
it's going to be freeze-dried," said Vickie Kloeris, NASA's
manager for the space station's food system.

The study showed that only seven items -- all meats -- would be
edible after five years, said NASA food scientist Michele
Perchonok, with the Johnson Space Center in Houston.

A round-trip mission to Mars is estimated to take 18 months and
the bulk of the food might be put in place before the crew even
launches. Add on another year or two to produce and pack the food
and that leaves scientists tasked to come up with processes and
packages that will keep food viable for more than five years.

The longest-lasting foods in the NASA study were salmon and tuna,
followed by pork chops, meatloaf and three chicken entrees.
Vegetables fared the worst.

Thirty Johnson Space Center employees rated the foods on a
variety of factors, including flavor, aroma and texture.